Grinding machine



NOV. 2, 1943. CRAMER 2,333,411

GRINDING MACHINE Original Filed July 30, 1940 3 Sheets-Sheet l Nov. 2, 1943. H. CRAMER 2,333,411

GRINDING MACHINE Original Filed July 50, 1940 3 Sheets-Sheet 2 NOV. 2, 1943. H, CRAMER 2,333,411

GRINDING MACHINE Original Filed July 30, 1940 3 Sheets-Sheet 3 F I G- 7.. 290

MW ml? 326 6%! A M 322 M 320 4M0 H5 A 7 raw/v.5

Patented Nov. 2, 1943 T r UNITED sTATEs raTENT OFFICE GRINDING MACHINE Raymond H. Cramer, Newark, N. J., assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Original application July 30, 1940, Serial No.

348,398, now Patent No. 2,311,213, dated February 16, 1943. Divided and this application April 30, 1942, Serial No. 441,163

12 Claims.

This invention relates to grinding machines and comprises all of the features of novelty herein disclosed. An object of the invention is to provide improved means for controlling the relative feeding movement between an abrading feed. The grinding wheel F has a preliminary membe and a Work piece. Another object is to quick advance controlled by a, piston and cylinprovide suitable slides for supporting, guiding and der unit to a position ready to grind. Subseadjusting into position the member which is fed, quent slow feed is controlled by a rotary cam opthe member fed being herein shown as the grinderated by a vane in a short cylinder which has ing wheel. Another object is to provide an ima needle valve and a check Valve. proved feed mechanism wherein the grinding The work head H comprises a-housing in wheel or other fed member is brought rapidly which a hollow spindle 22 is journalled for rotatowards the co-operating member, as by a piston tion by bearing sleeves 24 and 26 having bearing and cylinder unit, and is then fed slowly under inserts 28 and 30. Endwise movement of the control of a cam and a cam follower one of which p ndle, i prev n by a p ir of pr e b l is turned by a second piston and cylinder unit of bearings 32 r ged back to back, the inner race the rotary vane type connected to the first unit. Tings ein p d o the p d e by a nut 34 This application i a di i i of my copending and the outer race rings being clamped between application Serial Number 348,298, which maa a ng housi g 6 d a h d c p tured as Patent No. 2,311,213, Feb. 16, 1943. 20 38 having a seal The spindle is driven by In t drawings a wide belt pulley 42 enclosed within a guard 44. Fig. 1 is chiefly a vertical section of the work The l y is de W e to provide for axial adhead with wheel feedin mechanism shown in justment of the work head with respect to its front elevation, driving means. At the chuck end the spindle is Fig. 2 is a left end view of the compensating protected y a double Seal and the le h mechanism a flange carrying a water slinger 48. The work is Fig. 3 is-a front view of the compensating slide clamped to he chuck by clamping fin ers 68 opand the wheel slides mounted thereon, the slides era/ted by a 5111mm? Operated draw rod 52 being in a different position from that of Fig. 1. w tending through e hollow p d e he wide Fig. 4 is a side view and Fig. 5 is a sectional pulley 42 is driven by a belt I31! running p s a i of id whee1s1ide5 take-up idler pulley I32 mounted on a spring Fig. 6 is an exploded view of parts appearing in Dressed arm the belt ru ning around a pul- 3 ley I36 on a shaft I38 journalled in a housing Fig 7 is a Sectional View of the t cylinder I40 on a plate I42 having a hollow trunnion I 44 which contr l the h el lide, through which a suitable drive extends to a spiral Fig. 8 is an enlarged cross sectional view of the r I t e shaft I33. T Plate I42 can b ho t mind r of Fi 7, oscillated for some purposes but for present pur- Fig. 9 is a sectional view of the needle valve in Doses is swung to a selected angular position and the region of line I4 of Fig. 8. g clamped by a bolt I45 passing through a slot I48 Fig. 10 is a sectional view of the check valve in to a main frame. The housing I40 has a raised the region of line I5 of Fig. 8. ortion I with a dovetail tongue I58 on which Fig. 11 is a perspective view of the cam of Fig. the work head H is adapted for horizontal ad- 7 and associated part5 ,iustment as by means of a screw I 60 threaded This machine grinds an overhanging flange or 45 in a nut I52 and journalled for rotation in a conical shoulder 4 at the end of a tapered raceway 2 on the inner race ring 6 of a tapered roller bearing. There is a rib 8 at the small end of the ring and a relief groove III at each end of the raceway. The race ring is rotated by a work holder or chuck C on a work head H. The flange or shoulder is ground by a conical surface I2 at the conical edge of a tapering flange on a grinding wheel F which is dished and has its drive shaft supported in a slanting position above the bracket I64 on the work head. An ejector E, in the form of a pivoted fork embracing the chuck next to the work, is secured to a rock shaft I68 rockably supported by a forked bracket IIIl. An arm I12 is pinned to the rear end of the shaft and is connected by a loose pivot I14 to an actuating bar I16 operated by a pull solenoid I84.

On the top of the work head is a dovetail tongue I94 on a plate I96 to guide a compensating slide I98 which is adjusted by a screw 200 threaded in a nut 202 and joumalled for rotation without endwise movement in an angle bracket 204 having one leg fastened at the end of the plate I96. The feed screw has a knob 206 for manual operation and is keyed to a ratchet wheel 208 forautomatic adjustment. Swinging on the hub of the ratchet wheel is a. lever 2 I carrying a pawl 2l2. A coil spring 2|4 urges the lever in one direction to bring an adjustable stop.

screw 2l6 against a face on the bracket 204, this screw adjustin the stroke of the pawl. The end of the lever is connected by a link to a plunger 2 H! on a pull solenoid 22!] mounted .onv the other leg of the bracket 204. Wires leading to the solenoid are mounted on a clamp 222. The solenoid is suitably actuated at every'xnachine cycle as in the parent application to feed the compensating slide I98 to the left to compensate for wear and dressing of the wheel F.

The compensating slide has an upstanding web 224 which supports a swivel plate 226 having ways forgui'din'g a slide whichadjusts the grinding wheel -F up or down towards or from the work, the'angle or direction of feed being adjustable also. Pressed into a hole in the Web 224' is a'pi-vot pin 22! which pivotall'y supports the swivel plate 226 by-entering a hole therein. The web 224*al'sd has arcuate slots 228 through which clampirigbolts 230 are passed into tapped holes in the swivel plate; one tapped hole being in a side lug 232' on' the swivel plate and the other at the center line. The swivel plate has a'dovetail tongue 234 on the front to fit a dovetail way in a slide 236, the slide being adjustable manu'any' up and down by a screw 238 threaded in aitapped' hole in the swivel plate and immense for'rotation without endwise movemen'tin a; lug 240 'on the rear of-the slide at the top. This'is a preliminary or set-up manual adjustment and another slide. orblock on the slide 235 feeds the; wheel F towards or from the workautomatically.

'The front face of the slide 236 has bolted thereto afixed 'gib 2'42h'aving a V-shaped slideway" m'atingwith a similar slideway on a gib 244 which is adjustable by screws 2.46 threaded in side lugs248 on the slide. The mating ways form a slideway for 'a feed block or slide 250 which is bolted 'tolthe rear or bottom face of an angular extension 25.2 on a sliding spindle hous ing12li4;- in ,which the. slanting drive: shaft of! the grinding wheel F is journalled'by any suitable bearings. The; shaft. has a wide pulley. 255 driven by a belt from a. suitable motor. The angular extension is securedito the-end of -a. piston rod .255- Y which.. passes. freely through a. hole in .a, flange. 258 at the upp rend of. the slide 236., therpiston. rod; beingconnected toga. piston in, a ,cy1in,der'ZEDQWhichis bolted to. the upper face. of the flange 258. The. spindle housing and its extension, together withthe attached block 250' form a.feedfslidewhich is rapidly fed. towards the work ready to begin grinding, this slide afterwards feeding forwardly very slowly under control of a cam which is rotated by a vane in a cylinder attached to the top ofthe cylinder as willlater-appear.

The sliding return or upward movment of the grinding wheel is made to'control a switch 252 having a plunger engaging a switch lever-264 and urging it towards a stoppin 268, the switch being secured'bya bracket to the flange 258. The lever is pivoted on a pivot screw 2') between a thick. spacer 212. and a thin spacer. 214-, these parts being heldbylock nuts on the-pivot screws.

The switch lever lies in the path of a. dog 216 pivoted on a plate 218 and urged towards a stop pin 288 by a light coil spring 282. The plate has elongated slots and is adjustably secured by clamping screws 284 to a bracket on the angular extension 252. On the return or upward movement of the grinding wheel and its slide, the dog 2'76 will actuate the switch lever 264 and close the switch but upon the advance the dog will swing idly over the hooked end of the switch lever. This switch controls a solenoid, as explained in the parent application, and reverses a valve to actuate. a. dressing device, which dresses the wheelzl 'alang its conical operating face [2.

Piston. and cylinder ,feed

' The cylinder 26!! has its upper head 290 of large diameter and forming the lower head of a short cylinder 292 having an upper head 294.

The piston rod 256, including a detachable extension 256A which clamps against the piston, passes: through both cylinders and- .throiigh a sleeve'zfifi joumalled in the cylinder heads and turning freely .around the piston rod extension. A rockable piston or'vane 298 is 'attached-to the sleeve :by screw bolts and is adapted to operate between: stop screws 300- and302 fastened to the ends at a segment 344 bolted to one; cylinder head; When feeding the: Wheel forward; pressunefiuid enterstheicylinderflll through a port 3%. andrenters the cylinder 292 through a. branch port-3118, port 308- coming in near the-stop screw 303. Exhaust fluid leaves :the cylinder 260 at a port; 81:6 and leaves cylinder! through a: small port 342-. leading to a. needle or throttle valve 314 which. is. adjustable by a hand wheel 3+6. Port 342 communicates past the needle valve with a longitudinal port 318 leading to a, circumferential part 320' which comes into a 10m gitudinal; exhaust:- port 1M2. of :largediameter. Movement. ot the vane or rockable pistonlBB' in one direction is thus very slow depending on the setting. of theneedle valve.

When the. flow of fluid isreversed, the port 322 becomes the entrance port and. port 308 becomes. the. exhaust port. The entrance. port 322 leads through a ball seat 324'toliftaba11 check. valve 326 towards aloose. stop pin 328,.and permit the, pressure fluid to enter the. cylinder rapidly. through a port 330; Thus the vane will return rapidly, In. the slow advance, the ball check valve is of course seated to prevent exhaust of fluid therethrough and toco npelthe' fluid to pass through ports 312 and 320'a'n'd the interposedneedlevalve. v

The extension 256A of the piston rod' 2561s threaded at the end to receive a nut 3332 holding a block 33'4having trunnions for a' pair of'cam follower rollers 336 adapted te'eri age an-an: nul'ar-cam 338. The cam body is connected by clutch teeth 339 to the end 'of" the sleeve 296 and'bears against a ball thrustbearing 340 'inside a guard 342. 'Iheroll'ers are in'itiallysepa rated from the cam butdescend rapidly-with the piston rod until stopped by the" cam, the small andldevious passagesin the short -cylinder 292 "being inactive until the piston rod" is stopped: Thereafter the pressure will" buildup and cause the fluid to exhaust through the restricted pas sages and thereby control a slow rotation ofthe vane and the cam; Thuslthere'ls 'a, rapidmwe ment ofthegrinding wheel'towards the work' with a slow feed for actual grinding. The cam has a low portion and a littl'e rise providing-a dwell and 'aslight preliminary retractionat the conclusion of grinding. When the flow of pressure fluid is reversed, it is apparent that the piston rod 255 has control and hence the wheel will rapidly rise or return to its initial position, the cam rolls 336 moving away from the cam.

I claim:

1. In a grinding machine, a grinding wheel, a feed slide supporting the grinding wheel, a piston and cylinder unit having a piston rod connected to the feed slide, a second cylinder having a rotory vane, a cam connected to the vane, a cam follower on the piston rod, and means for causing fluid pressure to successively actuate the piston and the vane to produce a rapid initial movement of the feed slide followed by a slow feed under control of the cam.

2. In a grinding machine, a grinding wheel, a feed slide supporting the grinding Wheel, a piston and cylinder unit having a piston rod connected to the feed slide, a second cylinder having a rotary vane, a cam connected to the vane, a cam follower on the piston rod, and means for causing fluid pressure to successively actuate the piston and the vane to produce a rapid initial movement of the feed slide followed by a slow feed under control of the cam, said means including wide open passages communicating with the piston and a restricted passage communicating with the vane.

3. In a grinding machine, a grinding wheel, a feed slide supporting the grinding wheel, a piston and cylinder unit having a piston rod connected to the feed slide, a second cylinder having a rotary vane, a cam connected to the vane, a cam follower on the piston rod, and means for causing fluid pressure to successively actuate the piston and the vane to produce a rapid initial movement of the feed slide followed by a slow feed under control of the cam, said means including wide open passages communicating with the piston and a needle vaive interposed in a passage communicating with the vane.

4. In a grinding machine, a grinding wheel, a feed slide supporting the grinding wheel, a piston and cylinder unit having a piston rod connected to the feed slide, a second cylinder having a rotary vane, a cam connected to the vane, a cam follower on the piston rod, and means for causing fluid pressure to effect a rapid initial movement of the feed slide followed by a slow feed under control of the cam in one direction and a rapid retreat without slow movement in the opposite direction, said means comprising a needle valve and a check valve in the passages leading to the vane.

5. In a grinding machine, a grinding Wheel, a feed slide supporting the grinding wheel, a piston and cylinder unit having a piston rod connected to the feed slide, a second cylinder mounted upon the first and having a rotary vane, a cam connected to the vane, the piston rod passing through both cylinders and having a cam follower normally spaced from the cam, and means for causing fluid pressure to successively actuate the piston rod to bring the cam follower against the cam and to turn the cam for controlling subsequent movement of the piston rod and the feed slide.

6. In a feed mechanism for controlling the relative feeding movement between a work piece and an abrading member, a slide, a piston and cylinder unit having a piston rod connected to the slide, a rockable member, an initially separated cam and a cam follower one of which is turned by the rockable member and the other shifted by the piston rod, a second cylinder unit for turning the rockable member, fluid inlet and exhaust passages leading to the cylinders, one of the passages leading to the second cylinder having a throttle valve whereby the piston rod brings the cam and the cam follower into contact at one speed and the rockable member controls further movement of the rod at a lower speed.

7. In a feed mechanism for controlling the relative feeding movement between a work piece and an abrading member, a slide, a rod connected to the slide, a rockable member turnable on the rod, an initially separated cam and a cam follower one of which is connected to the rockable member and the other connected to the rod, means for urging the rod in a direction to bring the cam and the cam follower into contact, and means for thereafter turning the rockable member to control further movement of the rod at a lower speed.

8. In a feed mechanism for controlling the relative feeding movement between a work piece and an abrading member, a slide, a rod connected to the slide, a rockab-le member turnable on the rod, an initially separated cam and a cam follower one of which is connected to the rockable member and the other connected to the rod, means for urging the rod in a direction to bring the cam and the cam follower into contact, a cylinder and piston unit for turning the rockable member, fluid inlet and exhaust passages leading to the cylinder, and throttling means in one passage for postponing movement of the rockable member until said contact occurs.

9. In a feed mechanism for controlling the relative feeding movement between a work piece and an abrading member, a slide, a rod connected to the slide, a rockable member turnable on the rod, a cam and a cam follower one of which is connected to the rockable member and the other connected to the rod, a cylinder and piston unit for shifting the rod endwise in opposite directions, a second cylinder and piston unit for turning the rockable member around the rod, fluid inlet and outlet passages leading to the cylinders, one passage having a portion common to both cylinders, and the other passage to the second cylinder having a throttle valve and a one-way check valve to cause slower turning of the rockable member in one direction than the other.

10. In a feed mechanism for controlling the relative feeding movement between a work piece and a grinding wheel, a work head having a, work rotating spindle, a feed slide having means to rotatably support the grinding wheel, means for guiding said slide at an angle to the work spindle. said guiding means having a cylinder attached thereto, a piston rod projecting from the cylinder to actuate the feed slide, a swivel plate supporting the guiding means, and a supporting member mounted on the work head and having a pivotal support for the swivel plate to provide for adjustment of the angle of feed.

11. In a feed mechanism for controlling the relative feeding movement between a work piece and a grinding wheel, a work head having a work rotating spindle, a feed slide having means to rotatably support the grinding wheel, means for feeding the, slide at an angle to the work spindle, a compensating slide mounted on the work head, means for shifting the compensating slide along the work head parallel to the work axis, a swivel plate pivoted to the compensating slide to adjust the angle of approach of the work and the wheel,

said swivel plate having means mountedfthereon to guidezandsupport therfeedislidez 7:; r

12. In a; feed mechanism for controlling the relative "feeding movement/between a; work piece and a. grinding wheel, a; work'head having azwork rotating spindle, a compensating slide mounted on the work head, means for' shifting thescompensating. slide: along the work head; parallels-to the work axis, a swivel plate pivoted to the come pensating: slides. toz-adj 11st the: angle of; approach ofxthe:workaandthe'wheeh asecond slide guided byathe swiveluplate; meansforadjusting the second siidemr theswivel plate alongsaidangleof approach, a feed-slide-guidedby. the second slide and having means to support the grinding wheel, and means. supportedf by the second ,slidefor shifting the feedislide thereon.

RAYMOND'H. CRAMER. 

